I see I've garnered some interest on my last post regarding vampires and speculative biology, therefore I'm happy to share my thoughts and the conclusion I've reached in terms of vampire anatomy
So to preface this, I actually am not a huge fan of vampires in terms of how modern media has portrayed them; compared to more fascinating yet gruesome concept of lycanthropy and its metaphorical parallels to humanity, identity, and horrific transformation, Vampires just... lacked that appeal to me with the simplicity of an otherwise abnormal human with pointy ears and having a thirst for blood.
When you look at it from the biological lens in regards to actual vampire bats, it's fascimating but incredibly ridiculous to think that a creature could subsist entirely on blood; it's an extreme specialization that only works in oh so many critters due to how unsustainable it to just live off of a liquid diet.
There's also the matter of just the overall appearance; as fun as it is drawing winged humanoids that still retain human limbs, a quick descent into anatomy made me realize how heavily modified the skeleton had to be to accommodate for a naturally mult-limbed vertebrate because at the end of the day, bat wings (and bird wings as another reference) are modified arms and hands that, with the addition of normal arms/hands, would be an anatomical nightmare.
In trying to come up with a plausible explanation as to how a living vampire would anatomically work, I came to 2 separate conclusions: the vampire would either have a modified keel (an expanded sternum in birds) that would allow for the place of grasping limbs positioned lower along the body in addition to a pair of wings (thus making them 4 limbed), OR (the more plausible idea in my mind) they would be more anatomically similar to a pterosaur in which only 1 finger is modified to act as the wing, allowing the other 4 fingers to be free at the cost of reduced strength (but which is then made up for in the back limbs, which would be anatomically similar to that of a primate with the bonus of human hand flexibility).
There's also the matter of sociability and behavior in vampires that I think is rather ironic; often, older media portrays them as brooding figures that live solitary lives and compete with another, but funnily enough vampire bats are highly social (well the females are at least) and have been documented sharing food and participating in allogrooming; ergo, I like to think they'd be more sociable, perhaps even on par with the modern wolf in terms of social dynamics (albeit modified).
Lastly, the food issue came to my attention and it occurred to me that perhaps rather than being obligatory sanguivores, vampires are instead facultative sanguivores and live more akin to scavengers or carrion eaters like vultures; that is, they stalk prey that's injured or on the verge of death. The prey in question I imagine would consist of medium to large ungulates like wild boar, deer, and elk as opposed to humans (I think "attacks" would be misinterpreted much like those of other apex predators e.g. perhaps the vampire was feasting on a human that was already dead or was extremely desperate for food); regarding their hunting hours, naturally they are nocturnal, but I think moreso cause they're sensitive to sunlight in the way any nocturnal critter is: the eyes are better suited for the night (light won't kill them, it's just not easy on the vision nor, perhaps, sensitive skin).
For a more modern interpretation regarding the whole thing with blood, I had the thought that as opposed to vampire bats who go for fresh blood, I thought that perhaps they could consume coagulated blood as it's a common ingredient in blood sausage and soups in other countries (contrary to American media). This actually then made me realize it seems no one's thought of the word building concept of vampire farmers who raise their own livestock for personal consumption (imagine if you will, a vampire farmer hiring human farmhands with livestock maintenance cause you can only do so much with hands on your legs and only 4 working fingers attached to a wing). Alternatively there are those with hunting licenses permitted to stalk the environment for prey around certain times of the year).
I think... I think I've gotten most of what I had in mind out of my head (although knowing me, I most likely forgot to note a thing or 2), jumbled as it is; if anyone is further interested in the anatomical concepts, I'd be happy to post them on my other blog where I mostly post conceptual work
